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spi/spi-atmel: detect the capabilities of SPI core by reading the VER…
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…SION register.

The "has_dma_support" needed for future use with dmaengine driver.

[Fixed some unneded ternery operators -- broonie]

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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Wenyou Yang authored and Mark Brown committed Apr 1, 2013
1 parent faa98f7 commit d4820b7
Showing 1 changed file with 50 additions and 16 deletions.
66 changes: 50 additions & 16 deletions drivers/spi/spi-atmel.c
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Original file line number Diff line number Diff line change
Expand Up @@ -22,9 +22,8 @@
#include <linux/platform_data/atmel.h>
#include <linux/of.h>

#include <asm/io.h>
#include <asm/gpio.h>
#include <mach/cpu.h>
#include <linux/io.h>
#include <linux/gpio.h>

/* SPI register offsets */
#define SPI_CR 0x0000
Expand All @@ -39,6 +38,7 @@
#define SPI_CSR1 0x0034
#define SPI_CSR2 0x0038
#define SPI_CSR3 0x003c
#define SPI_VERSION 0x00fc
#define SPI_RPR 0x0100
#define SPI_RCR 0x0104
#define SPI_TPR 0x0108
Expand Down Expand Up @@ -71,6 +71,8 @@
#define SPI_FDIV_SIZE 1
#define SPI_MODFDIS_OFFSET 4
#define SPI_MODFDIS_SIZE 1
#define SPI_WDRBT_OFFSET 5
#define SPI_WDRBT_SIZE 1
#define SPI_LLB_OFFSET 7
#define SPI_LLB_SIZE 1
#define SPI_PCS_OFFSET 16
Expand Down Expand Up @@ -180,6 +182,11 @@
#define spi_writel(port,reg,value) \
__raw_writel((value), (port)->regs + SPI_##reg)

struct atmel_spi_caps {
bool is_spi2;
bool has_wdrbt;
bool has_dma_support;
};

/*
* The core SPI transfer engine just talks to a register bank to set up
Expand All @@ -204,6 +211,8 @@ struct atmel_spi {

void *buffer;
dma_addr_t buffer_dma;

struct atmel_spi_caps caps;
};

/* Controller-specific per-slave state */
Expand All @@ -222,14 +231,10 @@ struct atmel_spi_device {
* - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
* - SPI_CSRx.CSAAT
* - SPI_CSRx.SBCR allows faster clocking
*
* We can determine the controller version by reading the VERSION
* register, but I haven't checked that it exists on all chips, and
* this is cheaper anyway.
*/
static bool atmel_spi_is_v2(void)
static bool atmel_spi_is_v2(struct atmel_spi *as)
{
return !cpu_is_at91rm9200();
return as->caps.is_spi2;
}

/*
Expand Down Expand Up @@ -263,15 +268,20 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
unsigned active = spi->mode & SPI_CS_HIGH;
u32 mr;

if (atmel_spi_is_v2()) {
if (atmel_spi_is_v2(as)) {
/*
* Always use CSR0. This ensures that the clock
* switches to the correct idle polarity before we
* toggle the CS.
*/
spi_writel(as, CSR0, asd->csr);
spi_writel(as, MR, SPI_BF(PCS, 0x0e) | SPI_BIT(MODFDIS)
if (as->caps.has_wdrbt) {
spi_writel(as, MR, SPI_BF(PCS, 0x0e) | SPI_BIT(WDRBT)
| SPI_BIT(MODFDIS) | SPI_BIT(MSTR));
} else {
spi_writel(as, MR, SPI_BF(PCS, 0x0e) | SPI_BIT(MODFDIS)
| SPI_BIT(MSTR));
}
mr = spi_readl(as, MR);
gpio_set_value(asd->npcs_pin, active);
} else {
Expand Down Expand Up @@ -318,7 +328,7 @@ static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
asd->npcs_pin, active ? " (low)" : "",
mr);

if (atmel_spi_is_v2() || spi->chip_select != 0)
if (atmel_spi_is_v2(as) || spi->chip_select != 0)
gpio_set_value(asd->npcs_pin, !active);
}

Expand Down Expand Up @@ -719,7 +729,7 @@ static int atmel_spi_setup(struct spi_device *spi)
}

/* see notes above re chipselect */
if (!atmel_spi_is_v2()
if (!atmel_spi_is_v2(as)
&& spi->chip_select == 0
&& (spi->mode & SPI_CS_HIGH)) {
dev_dbg(&spi->dev, "setup: can't be active-high\n");
Expand All @@ -728,7 +738,7 @@ static int atmel_spi_setup(struct spi_device *spi)

/* v1 chips start out at half the peripheral bus speed. */
bus_hz = clk_get_rate(as->clk);
if (!atmel_spi_is_v2())
if (!atmel_spi_is_v2(as))
bus_hz /= 2;

if (spi->max_speed_hz) {
Expand Down Expand Up @@ -804,7 +814,7 @@ static int atmel_spi_setup(struct spi_device *spi)
"setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n",
bus_hz / scbr, bits, spi->mode, spi->chip_select, csr);

if (!atmel_spi_is_v2())
if (!atmel_spi_is_v2(as))
spi_writel(as, CSR0 + 4 * spi->chip_select, csr);

return 0;
Expand Down Expand Up @@ -910,6 +920,23 @@ static void atmel_spi_cleanup(struct spi_device *spi)
kfree(asd);
}

static inline unsigned int atmel_get_version(struct atmel_spi *as)
{
return spi_readl(as, VERSION) & 0x00000fff;
}

static void atmel_get_caps(struct atmel_spi *as)
{
unsigned int version;

version = atmel_get_version(as);
dev_info(&as->pdev->dev, "version: 0x%x\n", version);

as->caps.is_spi2 = version > 0x121;
as->caps.has_wdrbt = version >= 0x210;
as->caps.has_dma_support = version >= 0x212;
}

/*-------------------------------------------------------------------------*/

static int atmel_spi_probe(struct platform_device *pdev)
Expand Down Expand Up @@ -970,6 +997,8 @@ static int atmel_spi_probe(struct platform_device *pdev)
as->irq = irq;
as->clk = clk;

atmel_get_caps(as);

ret = request_irq(irq, atmel_spi_interrupt, 0,
dev_name(&pdev->dev), master);
if (ret)
Expand All @@ -979,7 +1008,12 @@ static int atmel_spi_probe(struct platform_device *pdev)
clk_enable(clk);
spi_writel(as, CR, SPI_BIT(SWRST));
spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
if (as->caps.has_wdrbt) {
spi_writel(as, MR, SPI_BIT(WDRBT) | SPI_BIT(MODFDIS)
| SPI_BIT(MSTR));
} else {
spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
}
spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
spi_writel(as, CR, SPI_BIT(SPIEN));

Expand Down

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